1. Field of the Invention
This invention relates to a post-cure inflator for inflating and cooling a vulcanized rubber tire, and more particularly to an apparatus for automatically exchanging an upper rim in a post-cure inflator.
2. Description of the Related Art
Conventionally, a post-cure inflator of the vertically alternating type called turnover type is widely used which includes two sets of upper and lower rims for holding a tire therebetween provided for a single cavity of a tire vulcanizing machine in order to make the inflating and cooling time for a vulcanized tire longer than one cycle time of the tire vulcanizing machine. The upper and lower rims of the post-cure inflator must necessarily be exchanged according to the size of a vulcanized tire. To this end, according to a conventionally common practice, the upper and lower rims of each set are mounted on upper and lower rim supports. respectively, by means of bolts.
Another post-cure inflator is also known and disclosed, for example, in Japanese Utility Model Laid-Open Application No. 55-169417 wherein a rim support has a hole formed therein and a securing member having a hooked portion which can be inserted into the hole of the rim support and can be contracted is secured to a rim and then the hooked portion of the securing member is contracted so that the rim can be mounted and removed readily.
However, particularly when an upper rim is to be mounted, the operator must lift the heavy upper rim to the upper rim support located at an upper portion of the post-cure inflator and then, while the upper rim is kept lifted, look into the upper rim from below and tighten the bolts. Even if the bolts are replaced by such hooked portions as described above, the operator must look into the holes formed in the upper rim support from below and perform the operation while the upper rim is kept lifted until the hooked portions are successfully fitted into the holes. In this manner, the operation of exchanging an upper rim has a problem that it is dangerous due to bad scaffolding and is difficult to perform since the weight of a rim increases as the diameter of a tire increases and besides an upper rim support is located at a higher location in the post-cure inflator while a lower rim, a lower rim support and so forth are installed at a lower location in the post-cure inflator which makes the scaffolding.